Biodiversity: UPSC Previous Year Questions (Environment and Ecology)

Explanation

The organisms Cicada, Froghopper, and Pond Skater are all insects. They belong to the class Insecta within the phylum Arthropoda. Cicadas are insects belonging to the order Hemiptera. They are known for their loud, distinctive calls and long life cycles with some species spending years underground as nymphs before emerging as adults. Froghoppers are also insects in the order Hemiptera. They are known for their jumping ability and the foam-like "cuckoo spit" produced by their nymphs. Pond skaters (also called water striders) are insects in the order Hemiptera. They are known for their ability to walk on water due to surface tension and their hydrophobic legs. (a) Cicada (b) Froghopper (c) Pond skater Fig: (a) Cicada, (b) Froghopper, and (c) Pond skater

Explanation

Marsupials are a group of mammals commonly referred to as pouched mammals, such as kangaroos and wallabies. These animals are characterized by giving birth to underdeveloped young, which then continue their development in the mother’s pouch (marsupium). They give live birth, but they do not have long gestation times like placental mammals. The pouch provides protection and access to nourishment during this critical growth stage. Statement-I is correct: Marsupials can be observed in regions spanning Australia, Papua New Guinea, and South America. They are not naturally found in India. Examples of marsupials include kangaroos, wallabies, wombats, opossums, bandicoots, and koalas. Statement-II is incorrect: These creatures predominantly inhabit arid and semi-arid areas, and they are not restricted solely to montane grasslands. Marsupials are highly adaptable and thrive in a variety of habitats, including forests, deserts, grasslands. Additionally, they coexist with predators like dingoes, eagles, and foxes in their natural environments.

Explanation

Option 1 is incorrect: Lion-tailed Macaque, also referred to as the wanderoo, inhabits the upper canopy of tropical evergreen rainforests and monsoon forests across various elevations. This species is endemic to the Western Ghats. They are diurnal which means it is active during the day and not nocturnal. IUCN Red List: Endangered Option 2 is correct: Malabar Civet is endemic to the Western Ghats of India. It is listed as Critically Endangered on the IUCN Red List. The Malabar civet is considered nocturnal and so elusive that little is known about its biology and ecology apart from habitat use. IUCN Red List: Critically Endangered Option 3 is incorrect: The Sambar, a large deer native to the Indian subcontinent and Southeast Asia, is crepuscular, active during twilight (morning and evening), and occasionally after sunset. Males are mostly solitary while females form small herds of up to 16 individuals. IUCN Red List: Vulnerable

Explanation

The waggle dance is a unique form of communication performed by honey bees (Apis mellifera) to convey information about the direction and distance of food sources, water, or potential nesting sites to other members of their hive. Worker honeybees, all of which are females, constitute the only bees typically observed flying outside the hive by the general populace. Bees perform two distinct types of dances: The Round Dance and the Tail-wagging or Waggle Dance. The waggle dance of honeybees has long been recognized as a behaviour that communicates in-formation about resource location from a foraging worker to her nest mates.

Explanation

Microorganisms are classified into three primary groups on the basis of their preferred range of temperature:

Psychrophiles (cold-loving microbes) Mesophiles (moderate - temperature - loving microbes) Thermophiles (heat-loving microbes).

Statement 1 is correct: Hyperthermophiles such as Pyrobolus and Pyrodictium can grow at temperatures exceeding 100°C especially in high-pressure environments like deep-sea hydrothermal vents.

Statement 2 is correct: Psychrophiles such as Colwellia psy-chrerythraea and Pseudomonas syringae can grow at temperatures as low as -10°C and remain metabolically active even at -20°C in environments like Arctic permafrost, deep-sea polar waters, and glacial ice. These microbes produce cryoprotectants such as antifreeze proteins to prevent ice crystal formation in-side their cells.

Statement 3 is correct: Acidophiles such as Ferroplasma acidar-manus and Acidithiobacillus ferrooxidans thrive in environments with pH as low as 0.5, such as acidic hot springs, acid mine drain-ages, and volcanic sulfur pools. These microbes have evolved mechanisms to pump out excess protons (H ions) to maintain internal pH stability. Some acidophiles like Thermoplasma lack a cell wall but possess specialized membrane structures to withstand extreme acidity.

Explanation

Orangutans are highly intelligent great apes known for their tool-using abilities. They have been observed breaking off small branches and using them as tools to scrape insects from holes in trees or logs. This behavior demonstrates their advanced cognitive skills, problem-solving abilities, and adaptability in foraging. None of the other listed animals.

Explanation

Statement 1 is correct: In India, Biodiversity Management Committees (BMCs) are established at the local level under the Biological Diversity Act, 2002. The National Biodiversity Authority (NBA) and State Biodiversity Boards (SBBs) work with BMCs to regulate access to biological resources and traditional knowledge, ensuring compliance with the Nagoya Protocol.

Statement 2 is correct: Biological Diversity Act, 2002 empowers BMCs to determine Access and Benefit Sharing (ABS) mechanisms for biological resources found within their jurisdiction. They can levy collection fees on any person or entity accessing biological resources for commercial use.

Explanation

Lemongrass is a tall herb that is widely distributed in tropical and subtropical regions of Asia, Africa, and Australia. Lemongrass is most frequently produced in China and India. The lemongrass herb is well known for its effectiveness at warding off mosquitoes and works as a mosquito repellent. It contains the chemical citronella, which aids in disguising the smells that mosquitoes use to target victims. A 2011 study found that the strong odour of lemongrass oil effectively killed or fully repelled more than 90% of the mosquitoes from a particular range of species.

Explanation

Savanna Biome is a particular kind of grassland biome made up of vast expanses of open grassland with few trees. Tropical and Semi-tropical savannas are two kinds of savannas. All continents excluding Antarctica have grasslands. The largest savannas are found close to the equator in Africa.

Option (c) is correct:

Frequent wildfires both natural (lightning-induced) and human-induced prevent the establishment of dense forests. Fires destroy young tree saplings before they can mature into large trees, thus maintaining grasslands. Savanna fires are a key ecological process that helps maintain the balance between grasslands and scattered trees. Large herbivores like elephants, zebras, and antelopes feed on young tree shoots, preventing forests from expanding. Grazing by animals ensures that tree cover remains sparse which allows grasses to dominate. Studies on African and Indian savannas have shown that herbivory is a critical limiting factor for tree growth. The limited and unpredictable rainfall pattern allows grasses to outcompete trees for available water. Savannas experience distinct wet and dry seasons leading to limited water availability. Trees require consistent moisture to grow into dense forests but in savannas prolonged dry periods hinder tree survival. Burrowing animals such as aardvarks and rodents and termites play a role in soil aeration and nutrient cycling. But they do not significantly prevent tree growth or forest development. Trees can grow in varied soil types and soil properties alone do not explain forest suppression.

Explanation

Transfer of pollen grains (shed from the anther) to the stigma of a pistil is termed pollination. Flowering plants have evolved an amazing array of adaptations to achieve pollination. Depending on the source of pollen, pollination is divided into three types, i. e. Autogamy, Geitonogamy and Xenogamy.

Statement 1 is correct: Butterflies are important pollinators for many flowering plants. Plant species particularly those that produce brightly colored, scented flowers with deep nectar tubes are adapted to butterfly pollination. A drastic fall in butterfly populations would result in reduced pollination, affecting plant reproduction and possibly leading to a decline in the population of such plant species.

Statement 2 is incorrect: There is no direct link between butterfly populations and fungal infections in cultivated plants. Fungal infections are influenced by factors like humidity, temperature, plant health, and soil conditions rather than by the presence or absence of butterflies.

Statement 3 is correct: Butterflies form a crucial part of the food chain, serving as prey for birds, wasps, spiders, and other insectivores. Many species of small birds (e.g., flycatch-ers, warblers, bee-eaters) depend on butterflies and their larvae (caterpillars) as a major food source. If butterfly populations decline then predators depending on them may suffer a population decline.